Amphibian

ABSTRACT

The present invention provides, with reference to FIG.  1 , an amphibian for use in land and marine modes comprising:
         a planing hull;   three wheel stations, two of the three wheel stations being front wheel stations provided one on each side of and in the front half of the amphibian, and the third wheel station being a rear wheel station provided in a central region in the rear half of the amphibian;   at least one wheel provided at each wheel station, each wheel being movable between a protracted land mode position and a retracted marine mode position;   land propulsion means to propel the amphibian on land in the land mode, the land propulsion means comprising at least one of the wheels; and   marine propulsion means to propel the amphibian on water in the marine mode, the marine propulsion means comprising at least two impellers or propellers provided one on each side of the rear wheel station.

The present invention relates to an amphibian and, in particular, to anamphibian having a three wheel configuration.

A number of road wheel and seating arrangement layouts have beenproposed and built for amphibians. The most popular layout, as for roadvehicles, is to have four wheels and sit-in seating provided across theamphibian in one or more rows. This convention provides stability andease of communication respectively. However, it also sets constraints onthe dimensions, weight, performance and manoeuvrability of theamphibian.

Two wheeled amphibians are also known, for example, from Buchanan (GB2,254,831). The size of hull needed to ensure flotation on water gives abloated appearance to the amphibian, reduces stability andmanoeuvrability on road, and hinders access to mechanical parts forservicing. Indeed, such amphibians tend to be compromised both on landand on water. For example, Buchanan provides extensible bellows on bothsides of his amphibian body, to act as stabilizers at low speed onwater.

Three wheeled road vehicles are known, the convention being to have asingle front wheel and two driven rear wheels. This allows a smallturning circle, and uninterrupted space for passengers and/or goods atthe rear of the vehicle. However, this layout is notoriously unstable onland. On the other hand, the three wheeled Morgan sports cars, which hadtwo wheels at the front and one at the back, are remembered withaffection over fifty years after going out of production.

Three wheeled amphibians are known, for example from Grzech (U.S. Pat.No. 5,690,046), who uses a single front wheel. The two rear wheels arecovered on water by complex hinged panels, which may stop working ifdamaged in collisions or if their mechanisms were clogged by water, orby fine debris, e.g. sand. Salt water may of course lead to corrosion.It is noted that Grzech does not provide a full description of theoperation of these covers. Grzech shows hinged panels which are hingedin one dimension, but need to be hinged in two dimensions.

Baker (WO 99/24273) discloses a three wheeled amphibian whose wheels,including a single rear wheel, are not retractable. The glazing, roof,and doors of Baker's amphibian add weight, cost, and complexity, andenclose the driver and passengers in a conventional sit-in vehiclearchitecture. Similarly, the driver and passenger sit side-by-side,meaning that the driver is offset from the amphibian centre line. Thisin turn necessitates handed steering, which increases complexity ofproduction in a small and fragmented niche market. When only the driveris aboard, there are potential problems in amphibian handling due tooffset weight distribution. The side-by-side front seating also sets aminimum width for the amphibian.

A further amphibian is disclosed by Maguire (U.S. Pat. No. 6,505,694).Essentially, this is a snowmobile adapted to float. It has two frontwheels and a rear endless track drive mounted on the centre line of theamphibian. Marine propulsion is effected by the track drive which isretractable within the bodywork when the amphibian is on water. Marinepropulsion by track drives has been found to be painfully slow even withexposed tracks; retracted tracks are even less efficient. Maguire'samphibian is also compromised by these tracks on hard surfaces. Trackdrives limit speed and manoeuvrability on metalled roads. A hard trackmade of steel will damage the road, a soft track will be damaged by theroad. Maguire's amphibian will stress its track particularly badly whenturning, as shear loads in opposite directions will be applied toopposite ends of each cleat or lag.

The present invention provides an amphibian as set forth in the appendedclaims.

In a first aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheel stations, two of the three wheel stations being front wheelstations provided one on each side of and in the front half of theamphibian, and the third wheel station being a rear wheel stationprovided in a central region in the rear half of the amphibian;

at least one wheel provided at each wheel station, each wheel beingmovable between a protracted land mode position and a retracted marinemode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least two impellers orpropellers provided one on each side of the rear wheel station.

In a second aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheel stations, two of the three wheel stations being front wheelstations provided one on each side of and in the front half of theamphibian, and the third wheel station being a rear wheel stationprovided in a central region in the rear half of the amphibian;

at least one wheel provided at each wheel station, each wheel beingmovable between a protracted land mode position and a retracted marinemode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller, wherein: the land propulsion means is independent of themarine propulsion means.

In a third aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

at least three wheels arranged in a three wheeled vehicle configuration,two of the wheels being front wheels provided one on each side of and inthe front half of the amphibian, and a third wheel being a rear wheelprovided in a central region in the rear half of the amphibian, eachwheel being movable between a protracted land mode position and aretracted marine mode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller, wherein:

the land propulsion means is independent of the marine propulsion means.

In a fourth aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheels, two of the wheels being front wheels provided one on eachside of and in the front half of the amphibian, and the third wheelbeing a rear wheel provided in a central region in the rear half of theamphibian, each wheel being movable between a protracted land modeposition and a retracted marine mode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller, wherein:

the land propulsion means is independent of the marine propulsion means.

In a fifth aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheel stations, two of the three wheel stations being front wheelstations provided one on each side of and in the front half of theamphibian, and the third wheel station being a rear wheel stationprovided in a central region in the rear half of the amphibian;

at least one wheel provided at each wheel station, each wheel beingmovable between a protracted land mode position and a retracted marinemode position;

a prime mover which in the land mode of the amphibian provides direct orindirect drive to at least one of the wheels;

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least two impellers orpropellers provided one on each side of the rear wheel station.

In a sixth aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheels, two of the three wheels being front wheels provided one oneach side of and in the front half of the amphibian, and the third wheelbeing a rear wheel provided in a central region in the rear half of theamphibian, each wheel being movable between a protracted land modeposition and a retracted marine mode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least two impellers orpropellers provided one on each side of the rear wheel station.

In a seventh aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheels, two of the three wheels being front wheels provided one oneach side of and in the front half of the amphibian, and the third wheelbeing a rear wheel provided in a central region in the rear half of theamphibian, each wheel being movable between a protracted land modeposition and a retracted marine mode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller, wherein:

the land propulsion means is independent of the marine propulsion means.

In an eighth aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheel stations, two of the three wheel stations being front wheelstations provided one on each side of and in the front half of theamphibian, and the third wheel station being a rear wheel stationprovided in a central region in the rear half of the amphibian;

at least one wheel provided at each wheel station, each wheel beingmovable between a protracted land mode position and a retracted marinemode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels; and

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller, wherein:

the marine propulsion means is driven independently of the landpropulsion means.

In a ninth aspect, the present invention provides an amphibian for usein land and marine modes comprising:

a planing hull;

three wheel stations, two of the three wheel stations being front wheelstations provided one on each side of and in the front half of theamphibian, and the third wheel station being a rear wheel stationprovided in a central region in the rear half of the amphibian;

at least one wheel provided at each wheel station, each wheel beingmovable between a protracted land mode position and a retracted marinemode position;

land propulsion means to propel the amphibian on land in the land mode,the land propulsion means comprising at least one of the wheels;

marine propulsion means to propel the amphibian on water in the marinemode, the marine propulsion means comprising at least one impeller orpropeller; and

a prime mover, wherein:

the marine propulsion means is driven by the prime mover independentlyof the land propulsion means.

In a tenth aspect, the present invention provides an amphibiancomprising at least three retractable wheels, at least two of theretractable wheels being retractable about an axis substantiallyparallel to, or offset by an angle α of up to 40 degrees from, alongitudinal axis of the amphibian, and at least one of the retractablewheels being retractable about an axis substantially parallel to, oroffset by an angle β of up to 40 degrees from, a transverse axis of theamphibian.

Thus, an amphibian is provided with good handling on water and inherentstability on land. It is capable of operation on land and on water withminimal operational compromise on either medium.

The applicant has combined the benefits of two spaced apart wheels atthe front of the amphibian and a central wheel at the rear to optimiseon land performance, but which is counter-intuitive to optimisingperformance on water due to the inherent track width at the front of theamphibian, with a narrowing pointed hull at the front provided betweenthe front wheels, which hull becomes wider rearwards along its length tooptimise on water performance, but which hull is counter-intuitive tooptimising on land performance due to the shape of the hull suggesting asingle central front wheel and two spaced apart wheels at the rear.

The present invention provides, in a further aspect, a powertrain for anamphibian as set forth in the appended claims. This provides a compactlayout of a powertrain for an amphibian.

For the avoidance of doubt, reference herein to a rider or a drivermeans the person controlling the amphibian.

Grzech describes a centrally mounted water jet unit, which ejects waterbetween the two rear wheels. The disclosed water jet unit would beincompatible with a single rear wheel, for packaging reasons.

Baker describes an amphibian propelled in water by vanes attached to therear wheel. The rear wheel must remain immersed in order to thrust theamphibian forward. This increases the drag of the amphibian in water,since half of the wheel and tyre are always under the water when theamphibian is operated in marine mode.

Grzech provides for retraction of a single front wheel by long-travelhydraulic suspension forks, with road steering disconnection by splineson the forks. This design is not readily adaptable to a pair of frontwheels.

Baker uses water skis which can be rotated beneath the front wheels toallow planing on water. This prevents the amphibian from leaning intoturns on water, reducing possible cornering speed.

Both Grzech (with articulated wheel covers) and Baker (with mudguardsrotating to become water skis) teach covering of wheels over water. Themechanisms necessary to move such covers can be difficult to maintain.Mechanisms and, where used, electric motors are exposed to a number ofaggressive substances such as salt water and sand, which are liable toerode, clog, corrode, or distort moving parts. The operation of thecovers may also be adversely affected by distortion of the covers and/ortheir mechanisms resulting from collisions, even with minor obstaclessuch as rocks under water. Furthermore, the covers may be visible on theoutside of the amphibian, and thus will need a class “A” finish formarketing reasons. Such a high gloss finish will be very vulnerable toscratching and chipping, leading to rapid deterioration in theappearance of the amphibian.

Surprisingly, the present applicant has found in trials of prototypeamphibians that such covers are not necessary to ensure good marinehandling. Furthermore, exposed wheels have the advantage that the tyrescan act as fenders. The tyres are especially effective in absorbingminor bumps if the wheels are retracted at an angle to the vertical.

Preferred embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings inwhich:

FIG. 1 is a perspective view from above of an amphibian according to afirst embodiment of the present invention, with the wheels protractedfor use in land mode;

FIG. 2 is a perspective view from below of the amphibian of FIG. 1;

FIG. 3 is a front elevation view of the amphibian of FIG. 1;

FIG. 4 is a side elevation view of the amphibian of FIG. 1;

FIG. 5 is a rear end elevation view of the amphibian of FIG. 1;

FIG. 6 is a top plan view of the amphibian of FIG. 1;

FIG. 7 is a bottom plan view of the amphibian of FIG. 1;

FIG. 8 is the same perspective view of the amphibian of FIG. 1, but withthe wheels retracted for use in marine mode;

FIGS. 9 to 14 correspond to the views shown in FIGS. 2 to 7 save thatthe views shown in FIGS. 9 to 14 show the amphibian with the wheelsretracted for use in marine mode;

FIG. 15 is a perspective view from above of an amphibian according to asecond embodiment of the present invention, with the wheels protractedfor use in land mode;

FIG. 16 is a perspective view from below of the amphibian of FIG. 15;

FIG. 17 is a front elevation view of the amphibian of FIG. 15;

FIG. 18 is a side elevation view of the amphibian of FIG. 15;

FIG. 19 is a rear end elevation view of the amphibian of FIG. 15;

FIG. 20 is a top plan view of the amphibian of FIG. 15;

FIG. 21 is a bottom plan view of the amphibian of FIG. 15;

FIG. 22 is the same front perspective view of the amphibian of FIG. 15,but with the wheels retracted for use in marine mode;

FIGS. 23 to 28 correspond to the views shown in FIGS. 16 to 21 save thatthe views shown in FIGS. 23 to 28 show the amphibian with the wheelsretracted for use in marine mode;

FIG. 29 is a schematic perspective view from above of a rolling chassisof the amphibian of FIGS. 1 to 28;

FIG. 30 is a schematic perspective view from above of a powertrainlayout and retractable rear wheel suspension assembly of the amphibianof FIGS. 1 to 28;

FIG. 31 is a schematic top plan view of the powertrain layout of FIG.30;

FIG. 32 is a schematic side elevation view of the powertrain layout ofFIG. 30;

FIG. 33 is a schematic side elevation view of an amphibian according toa third embodiment of the present invention, in a land mode operationstate;

FIG. 34 is a schematic side elevation view of the amphibian of FIG. 33,in a marine mode operation state;

FIG. 35 is a schematic underneath plan view of the amphibian of FIG. 33,in a land mode operation state;

FIG. 36 is a schematic rear elevation view of the amphibian of FIG. 33,in a land mode operation state;

FIG. 37 is a schematic underneath plan view of an amphibian andpowertrain layout according to a fourth embodiment of the presentinvention;

FIG. 38 is a schematic simplified partial-cross-sectional view of anamphibian according a fifth embodiment of the present invention;

FIG. 39 is a schematic partial-front view of an amphibian according to asixth embodiment of the present invention, showing a wheel in aprotracted vehicle-supporting position;

FIG. 40 is a schematic partial-front view of an amphibian according toFIG. 39, showing a wheel in a retracted position;

FIG. 41A is a schematic simplified partial cross-sectional view of anamphibian according to the present invention, having a step-down drive;

FIG. 41B is a schematic partial cross-sectional view of the step-downdrive of FIG. 41A;

FIGS. 42A and 42B are schematic cross-sectional plan views of portionsof hulls of amphibians;

FIG. 43 is a rear perspective view of a seventh embodiment of amphibianaccording to the present invention;

FIG. 44 is a schematic top plan view of an eighth embodiment ofamphibian according to the present invention; and

FIG. 45 is a schematic side elevation view of the amphibian of FIG. 44.

Referring first to FIGS. 1 to 7, there can be seen an amphibian 10 inits land mode having a forward bow end 12 and a rear stern end 14.

The amphibian 10 has three wheel receiving stations 50, 52, 54. Two arefront wheel stations 50, 52 provided one on either side at the front ofthe amphibian 10, while the third is a rear wheel station 54 provided ina central region at the rear of the amphibian 10. At least one roadwheel 51, 53, 55 is provided at each wheel station 50, 52, 54. Eachwheel 51, 53, 55 is connected to the remainder of the amphibian 10 byany suitable wheel suspension system which includes a wheel retractionmechanism for moving the wheels 51, 53, 55 between a lowered state forland use and a raised state for marine use. The front wheels 51 and 53are steerable and handlebars 60 are provided to enable steering of thesewheels. Alternatively, a steering wheel may be employed in place ofhandlebars. The rear wheel 55 is driven to propel the amphibian 10 onland. Alternatively, or in addition, one or both front wheels 51, 53 maybe driven (i.e. the amphibian may be one, two, three or all wheeldrive). Jet drive units 72, 74 (see FIG. 2) provide propulsion in marineuse.

The structure of the amphibian 10 comprises an upper deck section 30 anda lower hull section 40. The upper deck structure 30 is sealed to thelower hull section 40 around a peripheral planar edge 35 which is abovethe water line when the amphibian 10 is fully displaced in water. Thecomplete upper deck section 30 is detachable from the lower hull section40 as a single unit, and/or as separate panels. This permits ease ofaccess to internal components of the amphibian 10 for servicing, etc.

Air inlet openings (not shown) provide an entry for cooling air (whichmay or may not be fan-assisted) for use by the cooling systems of theamphibian 10. Air entrained via these inlets is eventually exhausted viaoutlets (not shown). Between the air inlets and air outlets, a doradesystem is installed to prevent the ingress of water. The dorade systemfacilitates righting of the amphibian on water by use of a labyrinthineair inlet passage system to prevent the ingress of water should theamphibian 10 be inverted in use in the marine mode.

Sit-astride seating 34 is provided for a driver and passengers of theamphibian 10. Step through openings (not shown) may be provided in thesit-astride seating 34 to aid a rider/driver and/or passenger(s) gettingon and off the amphibian 10. Footwell areas 36, 38 are provided one oneither side of the sit-astride seating 34, each shrouded by bodyworkpositioned laterally outside of the footwell areas 36, 38 to provideprotection. These footwell areas 36, 38 may be provided with means tobail automatically any water shipped in use of the amphibian 10.

Front wheel arches 31, 32 and rear wheel arch 33 are provided so as toafford protection from spray. An instrument panel 62 is provided aheadof the steering controls to convey relevant parameters of the amphibian10 to the rider/driver. Additionally, rear view mirrors (not shown) maybe provided as a visual aid to the rider/driver. Furthermore, navigationlights may also be provided within or on the upper deck structure 30 inaccordance with the local legislative requirements.

The upper deck structure 30 forms an integral part of the entirestructure of the amphibian 10. It is a structural component and notmerely cladding. Typically it will take the form of a compositestructure (e.g. glass fibres or carbon fibres set in resin) although anysuitable manufacturing method may be employed. Where localised areas ofstrength are required in the upper deck structure 30, extra layers ormats of fibres may be laid down during manufacture. The deck 30 will beformed with localised reinforced areas in order to provide a completeforce transmitting path extending around the amphibian 10 in a completecircle in a plane orthogonal to a longitudinal axis of the amphibian 10,in order to provide resistance to torsional loads on the amphibian 10.

Referring in particular now to FIGS. 2 to 4 and 7, the underside of thehull 40 can be seen extending from the front bow section 12 to the rearstern section 14. Starting from the planar interface 35 with the upperdeck section 30, there is a wall 41 extending around a periphery of theamphibian 10 down to a lower hull surface 42. The overall displacementof the hull 40 provides stability when the amphibian 10 is operated athigh speed in marine mode, in particular because of the volume of hull40 spaced laterally from the centre line of the amphibian 10. As such,when cornering sharply, for example, an increase in righting force isexperienced as the angle of lean increases. The bodywork providedlaterally of the footwell areas 36, 38 in particular provide rightingforces spaced from the amphibian 10 centre line. Any or all such hullvolumes can be provided with buoyancy inserts to give residual buoyancy.

It will be appreciated that no cutouts are provided in the hull 40 inthe region of the front wheel stations 50, 52. Indeed, with reference inparticular to FIG. 14, it will be appreciated that the onlydiscontinuities 46, 48 and 49 in the hull are those provided at the rearof the hull 40 to accommodate the rear wheel station 54 and jet drives72, 74. These discontinuities 46, 48 and 49 have little effect on theperformance of the hull 40. As such, it has been possible to avoid theuse of any cover device to reconstruct the lines of the hull 40 when thewheel assemblies are retracted for use in marine mode.

A vee-hull section 44 is formed in the central lower surface 42 of thehull 40 and this can form or be provided with a keel which runs from thebow 12 along the length of the amphibian 10. Strakes or otherhydrodynamic aids (not shown) may be integrated in or provided on thehull 40. At the rear of the hull 40, water intake areas 46, 48 areincorporated for the jet drive marine propulsion units 72, 74 of theamphibian 10. In addition, a recess 49 is provided to accommodate therear wheel 55.

The design of the hull 40 is critical in determining the performanceachieved when the amphibian 10 is operated in the marine mode. Thepresent applicant has spent considerable time and effort in the designof the hull 40 which has resulted in a rather surprising shape ascompared to that usually expected for a planing water craft orampihiban. The hull 40 comprises a narrow uninterrupted (no cutouts) bowsection 43 having a dead rise angle of substantially 23 degrees alongits length, followed by a widening rearward section 45 having a deadrise angle of substantially 18 degrees along its length. This compareswith traditional planing hulls which start at the bow section with avery steep dead rise angle and these dead rise angles become moreshallow along the length of the hull towards the stern, typically endingat 5 degrees or less of dead rise angle. Prior art amphibians have hullsprovided with substantial cutouts or discontinuities to accommodateretractable wheel and suspension assemblies, these cutouts ordiscontinuities being provided with hull covers or entire slidablepanels to reconstruct the lines of the hull for use of the amphibian inmarine mode.

Since the sit-on seating 34 of the amphibian 10 is arrangedlongitudinally, the amphibian 10 is narrower than a passenger car.Aligning the engine longitudinally along the amphibian gives a bodyshape which is narrower in beam and deeper. Rather than adopting theflat planing hull common in the prior art, the applicant has adopted agreater dead rise angle for the agile marine handling this provides,accepting that this gives a need for a suspension with a lot of travelto give adequate ground clearance on land.

Whereas before amphibians such as that of Grzech strove to keep thetrack width of the wheels within the beam of the amphibian, theapplicant has realised that better land mode operation can be achievedif the track width of the front wheels 51, 53 of the amphibian 10amphibian is greater than the beam of the hull 40. The approach adoptedby the applicant does mean that wheels must be retracted through a largeangle in order to be clear of the amphibian waterline in marine use, butthe strategy does provide for a amphibian capable both on land and onwater.

Even with the small footprint of the hull 40 of the amphibian 10, thehull design 40 is capable of propelling the amphibian 10 up onto theplane with little difficulty in fast time periods. Furthermore, on-waterperformance of the amphibian 10 is not compromised and adequate groundclearance is available when operating the amphibian 10 in land mode.

The amphibian 10 has an overall length in the range of from 3.600 m to4.200 m, more preferably in the range of 3.800 m to 4.050 m, mostpreferably of substantially 3.950 m, an overall width in the range offrom 1.730 m to 2.000 m, more preferably in the range of 1.800 m to1.900 m, most preferably of substantially 1.850 m, and an overall heightin the range of from 1.200 m to 2.000 m, more preferably in the range of1.300 m to 1.500 m, most preferably of substantially 1.400 m. Thewheelbase length of the amphibian 10 is in the range of from 2.300 m to3.700 m, more preferably in the range of 2.400 m to 3.000 m, mostpreferably substantially 2.580 m and the track width of the front wheels51, 53 is in the range of from 1.400 m to 1.900 m, more preferably inthe range of 1.600 to 1.700, most preferably substantially 1.655 m. Thelength of the hull 40 is in the range of from 3.000 m to 4.200 m, morepreferably in the range of 3.300 m to 3.900 m, most preferablysubstantially 3.600 m. The maximum beam of the hull 40 is in the rangeof from 1.100 m to 2.000 m, more preferably in the range of 1.200 m to1.600 m, most preferably substantially 1.380 m, and beam of the hull 40between the front wheels 51, 53 in the front region 43 is less than thetrack width.

Referring now to FIGS. 8 to 14, these Figures correspond to the viewsshown in FIGS. 1 to 7 respectively, save that each shows the amphibian10 with its wheels retracted for use in marine mode.

Referring next to FIGS. 15 to 28, there is shown a second embodiment ofamphibian 10 according to the present invention. This second embodimentis broadly similar to the first, save that it is a smaller scale versionand comprises a ‘mudguard’ type design of wheel arch for front wheelarches 31′, 32′. Like reference numerals designate like componentsthroughout. The hull 40 comprises a narrow uninterrupted (no cutouts)bow section 43 having a dead rise angle of substantially 16 degreesalong its length, followed by a widening rearward section 45 having adead rise angle of substantially 12 degrees along its length.

The amphibian 10 has an overall length in the range of from 2.700 m to3.800 m, more preferably in the range of 3.000 m to 3.600 m, mostpreferably of substantially 3.323 m, an overall width in the range offrom 1.200 m to 1.800 m, more preferably in the range of 1.400 m to1.700 m, most preferably of substantially 1.600 m, and an overall heightin the range of from 1.100 m to 1.700 m, more preferably in the range of1.300 m to 1.500 m, most preferably of substantially 1.400 m. Thewheelbase length of the amphibian 10 is in the range of from 1.500 m to3.000 m, more preferably in the range of 1.900 m to 2.600 m, mostpreferably substantially 2.330 m and the track width of the front wheels51, 53 is in the range of from 1.000 m to 1.800 m, more preferably inthe range of 1.200 m to 1.600 m, most preferably substantially 1.430 m.The length of the hull 40 is in the range of from 2.400 m to 3.600 m,more preferably in the range of 2.700 m to 3.300 m, most preferablysubstantially 3.000 m. The maximum beam of the hull 40 is in the rangeof from 0.900 m to 1.500 m, more preferably in the range of 1.050 m to1.350 m, most preferably substantially 1.200 m, and beam of the hull 40between the front wheels 51, 53 in the front region 43 is less than thetrack width.

Referring now to FIG. 29, there is illustrated, schematically, a rollingchassis showing certain internal components of the amphibian 10. A primemover 80 can be seen which is a multi-cylinder internal combustionengine. Alternatively, any prime mover 80 such as electric, hydraulic,pneumatic, hybrid or otherwise may be beneficially employed. Wheelsuspension and retraction assemblies, powertrain, driveline andtransmission components can be seen, and these are more fully describedbelow with reference also to FIGS. 30 to 32.

The powertrain comprises an output shaft 81 leading drive from theengine 80 via a torsional damper 82 to a driveshaft 83. Driveshaft 83provides drive, via a forward-neutral-reverse gearbox 85, continuouslyvariable transmission (CVT) 90 (see pulleys 91, 92) and reduction drive86, to a land mode output shaft 94. Land mode output shaft 94 relaysdrive via a bevel gear set (not shown) located in the rear wheel hub 413to the rear wheel 55 during land use of the amphibian 10. Driveshaft 83also provides drive, via a belt drive system 100, to two marine modeoutput shafts 102, 104. Belt drive system 100 comprises an input/drivertoothed wheel 102, two output/driven toothed wheels 104, 106 and atoothed belt 108. Marine mode output shafts 102, 104 relay drive to thejet drive units 72, 74 during marine (and, optionally, land) use of theamphibian 10. The jet drive units 72, 74 may be permanently connected tothe engine 80 to be driven thereby at all times, whilst the rear wheel55 is driven (connected to the engine 80) only in its lowered(protracted) land use position. The forward-neutral-reverse gearbox 85,CVT transmission 90, reduction drive 86 and belt drive system 100 couldof course be replaced in other embodiments by a conventional automaticgearbox or a manual gearbox, or other powertrain and/or transmissionsystems and arrangements, as required.

Steering input is from handlebars 60. Various mechanisms may be used totransfer movement from the handlebars 60 to front steered wheels 51, 53.For example, the applicant's co-pending application published as US2006/0178,058 A1 discloses a steering system for a small amphibian withhandlebars, wherein road steering is automatically disengaged as theretractable suspension is retracted for use of the amphibian on water.However, this is essentially a cam-operated steering system, withoutgearing. If steering loads are sufficiently high that gearing and powerassistance are required, a steering system according to the applicant'spatent GB 2,400,082B may be used. This patent discloses an adaptation ofa power-assisted rack and pinion automotive steering system to anamphibian, arranged such that the power assistance also applies tomarine steering. This is helpful in damping out the water feedbackforces on the jet steering nozzle or nozzles which might otherwise causepainful and/or irritating feedback to the rider through the steeringcontrol.

The seating 34 in the amphibian 10 is provided substantially above theamphibian powertrain, with the handlebars 60 located in the front halfof the length of the amphibian. This gives a good driving position forboth marine and land use.

The front left-hand wheel suspension and retraction assembly 64 (thefront right-hand, partially shown, corresponds) and rear wheelsuspension and retraction assembly 400 are also shown in FIG. 29. Springand damper assemblies are provided for each of wheels 51, 53, 55.Retraction actuators 65 and 430 retract and extend these wheelsuspensions from their lowered positions (as is shown in FIG. 29) totheir raised positions, while spring and damper units 66 and 402, 404cater for normal suspension movement. Where actuator rams 65 and 430 arehydraulic, hydraulic fluid may be provided by a pump (not shown) poweredby the engine 80.

A fuller description of the rear assembly follows immediately below(with reference to FIG. 30) and, of the front assemblies, follows later(with reference to FIGS. 38 to 42B). However, it is to be noted thatthese are only examples of retractable suspensions which may be used.

Referring to FIG. 30, the retractable rear suspension 400 can be seen tocomprise a coil spring 402 and a telescopic damper or shock absorber404. First and second ends of damper 404 are pivoted to the amphibian 10at pivots 406 and 408 respectively. Pivot 408 is mounted on a cross beam410 which is part of a trailing arm assembly comprising two front angledarms 411 and two rear angled arms 412, one each provided on either sideof rear wheel 55, and a forward trailing arm 414. In normal bump andrebound movement, the trailing arm assembly will pivot around the pivot416 at the front of the trailing arm assembly, compressing and extendingspring 402 and damper 404 to give conventional damped suspensionmovement.

Upper pivot mounting 406 is mounted to retraction arm 420, which is inturn mounted at pivot 422 to bracket 424, which is firmly mounted to theframe (not shown) of the amphibian 10. A retraction ram 430 is mountedto bracket 424 at pivot mount 426, and to retraction arm 420 at pivotpoint 428. When ram 430 is actuated to retract, arm 420 is rotatedforwards, pulling damper 404 forward and up. This in turn lifts arms 412and thus the rear wheel 55 and trailing arm assembly until the rearwheel 55 is fully retracted. This movement is reversed for protractionof the wheel 55 when the amphibian 10 returns to land.

This mechanism is essentially a simplified version of the retractablesuspension disclosed in the applicant's co-pending application publishedas US 2006/0234,567A1, and shares its advantages in that off-the-shelfcoil springs and telescopic damper valves may be used to tune and adjustthe ride and handling of the amphibian 10 as required.

Although a hydraulic ram is shown as the actuator for the retractablesuspension, other actuators powered by compressed air or electricitycould be used instead, as required.

It will be appreciated that the above wheel suspension and retractionassembly mechanisms described above are given by way of example only,and any suitable alternative may be beneficially employed. Alternativemechanisms which may be used or adapted for suspension and retractionare described the applicant's patents and patent applications, such asU.S. Re. 36,901; U.S. Pat. No. 6,886,837B2; U.S. Pat. No. 6,945,832B2;U.S. Pat. No. 6,994,358B2; WO 04/039,613A1; U.S. Pat. No. 7,234,982B2;and US 2006/0,234,567A1, for example.

The powertrain components illustrated in FIGS. 29 to 32, i.e. the engine80 and transmission are built up on a frame platform which is thenconnected to the hull 40. This gives considerable advantage for ease ofmanufacture. Indeed it is envisaged that a chassis could be constructedwith a frame supporting all of the wheel suspension components, thewheel steering mechanism, the wheel retraction mechanism, the engine andthe transmission. This would considerably aid construction and repair.This is illustrated in FIG. 29 where a rolling chassis of the amphibiancan be seen stripped of the surrounding hull and deck sections. In FIG.29 there can be seen the engine, the transmission as well as thesuspension assemblies for the front and rear wheels, all mounted to acommon supporting structure.

A radiator (not shown) located at the front of the amphibian will coolthe amphibian's engine, at least in land use. The amphibian's engine canalso be cooled by a water/water heat exchanger (not shown) in marineuse, with water being drawn from beneath the amphibian to cool waterused by the engine cooling system.

Referring next to FIGS. 33 to 36, there is shown an amphibian 310according to a third embodiment of the present invention. The amphibian310 may include any or all of the features described above, in anycombination, with the following particular features.

The amphibian 310 comprises a body 312 joined to a hull 314 at jointline 313, hence being a buoyant vessel, having a pair of front wheels320 and a single rear wheel 322. It can be seen from FIG. 36 inparticular that hull 314 has a vee-shaped cross-section, to enable bothplaning and good handling on water.

The amphibian 310 includes a prime mover 316, which may be an internalcombustion engine or a similar power source, to provide power through atransmission 318 to the rear wheel 322. Alternatively, the prime movermay power the front wheels 320 only, or may power the front wheels 320and rear wheel 322.

The front wheels 320 are connected to the body 312 by suspension 324,and covered by mudguards 326. These guards may be fixed to the body orto the wheel suspensions by brackets (not shown). The rear wheel 322 isconnected to the body 312 by a trailing arm 328, which providessuspension for the rear wheel. The trailing arm may be double-sided asshown, or single-sided.

The rear wheel 322 and front wheels 320 are retractable by means ofretraction mechanisms. The retraction mechanisms for the front wheelsmay be as described in U.S. Pat. No. Re. 36,901, which is incorporatedherein by reference. The front wheel retraction mechanisms acts on thesuspension mechanisms to allow retraction and protraction of the wheels320.

The front wheel retraction mechanisms are operable to raise the frontwheels 320 by rotation about axes substantially parallel to alongitudinal axis of the body. Such axes are substantially horizontalwhen the amphibian is level. The front wheels 320 are retractable abovethe waterline when the amphibian is in a water mode.

The rear wheel retraction mechanism is operable to raise the rear wheel322 substantially vertically upwardly into the body 312. The rear wheel322 is retractable above the waterline when the amphibian is in a marinemode. One or more struts according to U.S. Pat. No. 6,886,837 B2 may beused to retract and protract arm 328.

The front wheels 320 can be steered to provide amphibian steering.Amphibian steering is controlled by handlebars 334 linked to the frontwheels 320. Alternatively, the handlebars may be linked to the rearwheel 322, or to both the front wheels 320 and rear wheel 322. A seat332 is located on the body 312 to support a rider of the amphibian 310,in a position facing forwardly and within reach of the handlebars 334.The seat 332 and body 312 allow the rider to sit along a centrallongitudinal axis of the amphibian 310, with the rider's legs on eitherside of the body 312. The driver is thus sitting astride the body.Preferably, the seat 332 is dimensioned to allow a passenger who can sitdirectly behind the driver on the seat 332. The passenger would also sitcentrally on the amphibian 310, astride the body 312.

FIGS. 33 and 34 show that the body 330 is provided with a front fender336 at a front end of the amphibian, and a rear fender 338 at a rear endof the amphibian. Headlights 340 for use on land and marine lights 342for use on water are provided at the front end of the amphibian. Acombination tail light unit 348 is provided at the rear end of theamphibian. This may incorporate a CHMSL (Centre High Mounted StopLight), where this is required by legislation.

Rear view mirrors 346 and a windscreen 344 are provided on the body 312.Left and right footwells 350, 352 are provided on the body 312, for therider and passenger to rest their feet. The footwells have drains 354.

With reference to FIGS. 33 and 35, a hull 314 is formed on the undersideof the body 312. The prime mover provides power to a marine propulsionunit. The marine propulsion unit may be a water jet unit 360, or anyother form of marine propulsion. The water jet unit 360 is preferablypositioned on a central longitudinal axis of the amphibian 310. Thewater jet unit 360 is preferably positioned forward of the rear wheel.The water jet unit has a jet intake 362, for drawing water into the jetunit; a driveshaft 364 from transmission 318; an impeller section 366;and a jet nozzle 368, through which water is expelled to providepropulsion.

At least one deflector 370 may be provided in order to divertaccelerated water from the jet nozzle 368 away from the rear wheel 322when the rear wheel is in a protracted position. This will occur whenthe amphibian first enters the water, when the water jet unit willprovide propulsion and the rear wheel 322 is yet to be retracted. Thedeflectors 370 form a chevron shape in plan view with the apex facingthe jet nozzle 368, in order to divert water either side of the rearwheel 322.

The deflectors 370 are located directly behind the jet nozzle 368, andare attached to the trailing arm 328. Hence, when the rear wheel 322 isfully retracted, the deflectors 370 are clear of water expelled from thejet nozzle 368. Ducts 372 and 374 may be provided to deflect waterrearwards. The exits from these ducts may be in the sides of the body,as shown, or more productively, in the transom. Alternatively,upstanding and substantially vertical walls (not shown) may be joined tothe outer edges of trailing arm 328, to deflect water rearwards alongboth sides of rear wheel 322.

FIG. 34 shows the amphibian 310 in a marine mode. The front wheels 320have been retracted by rotation above the waterline. The rear wheel 322has also been retracted above the waterline. The wheels 320, 322comprises tyres 376, 378 around their periphery. The front tyres 376 canact as fenders when the wheels are retracted, to absorb minor impacts tothe amphibian on water.

The rear wheel 322 is not provided with any cover on an underside whenretracted. The underside of the rear wheel 322 is therefore exposed towater in the retracted position. The front wheels 320 are similarly notprovided with a cover, and so are exposed to water when the wheels 320are retracted.

It may be found convenient for rear wheel 322 and tyre 378 to be exposedabove the rear bodywork when retracted, as shown in FIG. 34. However,this requires a gap in the bodywork, which may give rise to excess sprayon wet roads. FIG. 36 shows a lid 380 which may be connected to trailingarm 328 by a linkage (not shown) to lift it out of the way as the wheelis retracted. Unlike the linkages described above with reference toprior art, this linkage could be very simple—possibly just a straightprop—and would be well above the water line, and thus relatively immuneto the hazards of a marine environment.

Alternatively, a “mud flap” type spray guard (not shown) could bemounted to hull 314 near to rear fender 338. This could be retractedautomatically on water by a linkage to the trailing arm. In this case,however, the linkage may be partly located below the water line; andwould therefore have to be designed carefully to ensure durability.

Area 382 behind seat 332 may be used to provide either an open, or aclosed and waterproof storage area (not shown). It could also be used toprovide a fuel filler neck and opening (not shown), depending on thelocation of the amphibian fuel tank (not shown).

A fourth embodiment of an amphibian 910 and powertrain according to thepresent invention will now described, with reference to FIG. 37. Theamphibian 910 may include any or all of the features described above, inany combination, with the following particular features.

The amphibian 910 is a light weight version of the amphibian 310, and isintended to carry one person, being the rider. The amphibian 910comprises a body 930 being a buoyant vessel, and has two front wheels920 and a single rear wheel 922. The front wheels 920 and rear wheel 922are retractable by means of retraction mechanisms (not shown).

The rider sits on a seat astride the body 930 of the amphibian 910, withthe rider's legs on either side at least part of the body 930. The seatis aligned with a central longitudinal axis of the body 930. The seatand body 930 may be configured to support only one person, i.e. the seatis dimensioned only to support the rider and not a passenger.

The amphibian 910 in a land mode may be front wheel drive only. The rearwheel 922 is not driven in the embodiment shown in FIG. 37.

In a water mode, a water jet unit 960 can propel the amphibian 910. Thewater jet unit 960 has a jet intake for drawing water into the jet unit.The water is expelled from a jet nozzle to provide propulsion. The waterjet unit 960 and/or nozzle may be spaced apart from a centrallongitudinal axis of the amphibian 910. Alternatively, the water jetunit 960 and/or nozzle may be located on a central longitudinal axis ofthe amphibian 910.

Alternatively, the water jet unit may have two nozzles located eitherside of the rear wheel. The two nozzles may be connected to a singlewater jet unit, or may be connected one each to two separate water jetunits.

A prime mover 916 and transmission 918 are located between the frontwheels and the rear wheel. Transmission 918 may be a continuouslyvariable transmission (CVT). The prime mover 916 may be a transverselymounted internal combustion engine. Thus, the crankshaft axis extendssideways. The prime mover 916 is connected to the front wheels by aforwardly extending driveshaft 921 to a differential 923, thedifferential 923 being linked to the wheels in a known manner.

The transmission 918 is connected to the water jet unit 960 by a jetdriveshaft 961. The jet driveshaft 961 extends rearwardly of thetransmission 918. Since the driveshaft 921 and jet driveshaft 961 extendin opposite directions, there is no interference between the twodriveshafts. The driveshaft 921 and jet driveshaft 961 extendsubstantially parallel to the longitudinal axis of the body. Thisdrivetrain arrangement thus offers packaging advantages, as it placesthe land drive train at the opposite end of the amphibian to the marinedrive train, so that they do not conflict with each other spatially.

Front wheel drive may result in difficulties in leaving water on muddybanks, due to rearward weight transfer. However, the amphibian 110 mayleave water on prepared, hard surface slipways. The front wheel drivebrings an unexpected advantage, in that it offers a familiar “feel” toriders who have become accustomed to driven front wheels in road cars.

Pontoons 973 extend either side of the rear wheel 922. The pontoons 973are buoyant to improve the buoyancy of the amphibian. The water jet unit960 may be located in one of the pontoons 973. An output nozzle of thewater jet unit may extend from one of the pontoons. In the embodiment oftwo nozzles, one nozzle may extend from each pontoon. The two nozzlesmay be connected to a single water jet unit. Alternatively, each nozzlemay be connected to a separate water jet unit. One water jet unit may belocated in each pontoon.

The water jet unit(s) 960 and/or output nozzle(s) may be locatedadjacent to the pontoon(s).

The water jet unit 960 may be located substantially alongside the rearwheel 922. The water jet unit 960 extends substantially parallel to theplane of the rear wheel 922. Alternatively, the water jet unit 960 maybe located substantially ahead of the rear wheel 922, or substantiallyrearward of the rear wheel 922.

The wheels 920, 922 are connected to the body 930 by means of suspension(not shown). The suspension may be arranged to allow the body 930 tolean from side-to-side, i.e. about a longitudinal axis of the body. Thebody 930 can lean inwardly into corners in a similar manner to aconventional motorcycle. The ability of the body 930 to lean improvesthe cornering ability of the amphibian 910 on land.

The amphibian 910 may be provided with lights, a registration plate andany other means necessary to allow it to be road legal.

Referring next to FIGS. 38 to 42B, there are shown amphibians 1001according to fifth and sixth embodiments of the present invention. Theamphibian 1001 may include any or all of the features described above,in any combination, with the following particular features.

Amphibians should be well-suited for transporting occupants on both landand water equally efficiently. However, it will be understood from theprior art that most amphibians are more suited for transportingoccupants on either land or water, rather than both.

In order to provide good speed and manoeuvrability on land, suspensionarms, drive shafts and wheels are often located at lower regions of theamphibian, often protruding directly from a hull section of theamphibian and/or parts of the amphibian that would be submerged duringuse on water. Further, even though retractable suspension has beendescribed in the prior art, the suspension, drive shaft and/or wheel—inthe retracted position—is often left exposed to water, when in use onwater. Further, cut-out portions or other abnormalities to the shape ofthe hull may be provided in the hull section of the amphibian toaccommodate the suspension apparatus, drive shaft or wheel, when thewheel is in either of the retracted or protracted, vehicle-supportingpositions. The protracted position would be with the wheels in place foruse of the amphibian on land. Whilst the prior art designs provide hullsthat are buoyant and water-tight, a significant disadvantage is alsofound in that they often have cut-outs, abnormalities, and/or parts ofthe suspension apparatus, drive shaft or wheel that are submerged and/orsimply contactable by water—even when retracted—in use of the amphibianon water. This clearly alters the hydrodynamics of the hull section ofthe amphibian, making the amphibian perform less-well onwater—especially if the cut-outs, abnormalities, and/or parts of thesuspension apparatus, drive shaft or wheel are located in the planingsurface of the hull. In particular, large cut-outs for locatingretracted wheels can have a great impact on the speed andmanoeuvrability of the amphibian in use on water. For example, theamphibian may tend to “dig-in” at the back of an open wheel arch whenturning on water.

The present invention addresses the above-mentioned disadvantages of theprior art.

The present invention provides, in a further aspect, an amphibian foruse on land and water, comprising:

a hull having a planing surface which contacts water when the amphibianis planing on water;

at least one retractable suspension apparatus which is movable from avehicle supporting position to a retracted position; wherein

the retractable suspension apparatus comprises for each wheel upper andlower suspension arms that are pivotably connected at inboard ends to asupport structure within the hull and are pivotably connected atoutboard ends with a suspension upright, the upper suspension arm beingpivotably connected to the suspension upright by a first, upper pivotconnection and the lower suspension arm being pivotably connected to thesuspension upright by a second, lower pivot connection;

the suspension upright extends from the second connection, in adirection away from the first connection to a wheel hub mount locationat which the wheel hub is rotatably mounted on the suspension upright ata location remote from the first and second pivot connections;

the suspension upright when deployed in land use extends externally ofthe hull across an outer face and/or a side face of the planing surface;and

the lower suspension arm remains above a top of the planing surfacethroughout use of the amphibian on land.

Preferably, the suspension arms extend from within the hull over anouter edge of the hull.

Most preferably, the wheel hub is located a distance from the secondconnection at least equivalent to the distance between first and secondconnections. Further, the hub may be located at least around 5 cm, 10cm, 15 cm or 20 cm from the second connection.

Preferably, the wheel hub is rotatably mounted on the suspension uprightat a distal end of the suspension upright.

The wheel hub is, preferably, driven to rotate by a transmissionrelaying drive from a prime mover of the amphibian. The transmission mayhave a step-down drive section in which drive is taken from a locationat or above the lower pivot point and is relayed along or alongside thesuspension upright to the driven wheel hub.

Alternatively, the wheel hub may be driven by a hub motor. Preferably,the hub motor is a hydraulic motor or an electric motor.

Most preferably, the hull is a vee hull.

The amphibian may comprise a spring and damper assembly connectedbetween one of the suspension arms and the support structure.

Preferably, the amphibian comprises a retractable and extendableactuator operable to move the retractable suspension apparatus from thevehicle supporting position to the retracted position and vice versa.Further preferably, the actuator is also operable to vary groundclearance by varying the suspension height.

The support structure, preferably, comprises a rotatable support armwhich is pivotally mounted at one end to a fixed part of the supportstructure and to which is pivotally connected the actuator, the actuatorbeing pivotally connected at one end to the support arm and beingpivotally connected at the other end to a fixed part of the supportstructure, a/the spring and damper assembly being pivotally connected atone end to the rotatable support arm and at the other end to the lowersuspension arm.

According to a further aspect, the invention provides an amphibian foruse on land and water, comprising:

a vehicle body comprising a hull section without cut-outs in a planingsurface thereof, the planing surface for contacting water when in use onwater; and

at least one retractable suspension apparatus which is movable from avehicle-supporting position to a retracted position;

wherein, the at least one retractable suspension apparatus is connectedto the vehicle body to locate the at least one retractable suspensionapparatus externally of the hull section, in a vehicle-supportingposition, and has an elongate suspension upright which extends fromabove the planing surface to a wheel mount location, such that nocut-out is required in the planing surface to accommodate the at leastone retractable suspension apparatus in retracted and vehicle supportingpositions.

Preferably, the at least one retractable suspension apparatus isconnected to the vehicle body above the hull section, or above theplaning surface.

Preferably, the planing surface is directly contactable with water, whenin use on water.

Advantageously, the amphibian of the present invention substantiallyreduces, or removes totally, the necessity to have cut-outs,abnormalities, and/or parts of the suspension apparatus, drive shaft orwheel in the planing surface or that are submerged and/or simplycontactable by water—even when retracted—in use of the amphibian onwater. Accordingly, the hydrodynamics of the hull are improved.

An embodiment of the invention is provided by an amphibian for use onland and water, comprising at least one retractable suspension apparatuswhich is movable from a vehicle supporting position to a retractedposition, the retractable suspension apparatus comprising, in a vehiclesupporting position, upper and lower suspension arms operably-connectedto a suspension upright, the suspension upright for receiving one ormore wheels,

wherein the suspension upright comprises a step-down drive for receivingan input drive from a relative higher location and providing an outputdrive to a relative lower location. The step-down drive may be integralwith the suspension upright or may be provided in addition to thesuspension upright. When the step-down drive is provided in addition tothe suspension upright, the step-down-drive may be located alongside thesuspension upright and operably-connected thereto. The step-down drivemay be a geared apparatus, or a chain, a belt or a shaft drivenapparatus. The retractable suspension apparatus may comprise awishbone-type suspension.

A simplified view of part of an amphibian is shown in FIG. 38, in whichthe amphibian is, generally, indicated by reference 1001. The amphibian1001 includes a hull section 1002, a vehicle body 1003 and a suspensionapparatus 1004, including a wheel 1005. In this particular embodiment,the demarcation between the hull section 1002 and the vehicle body 1003is shown by the dotted line indicated by reference 1006. Mostpreferably, the hull 1002 provides a planing surface for contactingwater when the amphibian 1001 is planing. The amphibian 1001 includes aregular hull 1002 having a ‘V’ (vee) shape, for aiding manoeuvrability.The vehicle body 1003 includes any feature of the amphibian which is notdefined in relation to the hull section 1002 or the suspension apparatus1004. Accordingly, a suspension support structure 1011 is provided aspart of the vehicle body 1003, and is provided to receive parts of thesuspension apparatus 1004. The support structure 1011 may be directlyconnected to an internal surface of the hull 1002. The support structure1011 may also comprise part of a vehicle frame (not shown). Reference1070 indicates a possible water level on the hull 1002, below whichportions of the hull 1002 form a planing surface. However, it will beunderstood by those skilled in the art that the size and shape of theplaning surface depends upon, at least, the size of hull and the speedat which the amphibian 1001 is travelling on water.

As shown in FIG. 38, the suspension apparatus 1004 includes a suspensionupright 1007, also known as a king pin, and first and second lateralsuspension arms 1008 and 1009. The suspension upright 1007 isapproximately transverse to the suspension arms 1008, 1009, in avertical plane. An upper lateral suspension arm 1008 is connected to thevehicle body 1003 at a first end, and to the suspension upright 1007 ata second end. Both connections are pivotal connections allowing therespective parts of the suspension apparatus 1004 to move. The lowersuspension arm 1009 is also connected to the vehicle body 1003 and tothe suspension upright 1007. Again, the connections are pivotalconnections, allowing respective movement of the suspension apparatus1004. By way of example, the suspension apparatus 1004 can move in avertical plane to the ground and a horizontal plane to the ground, asshown by arrows indicated by references 1013 and 1014, respectively,when moving between vehicle supporting and retracted positions of theapparatus 1004. As can be seen from FIG. 1, the suspension upright 1007includes an extended suspension upright 1007A which extends from theconnection of the lower lateral suspension arm 1009 in an oppositedirection to the upper lateral suspension arm 1008. A hub 1010 forreceiving a wheel 1005 is located at or around a distal end of theextended suspension upright 1007A, in a location that is remote from thesuspension arm connections. Advantageously, provision of an extendedsuspension upright 1007A allows the suspension apparatus 1004 to beconnected to the amphibian 1001, such that, no cut-out is required inthe submerged surface—or planing surface—to accommodate the at least oneretractable suspension apparatus in retracted or in vehicle supportingpositions.

As can be seen from FIG. 38, the suspension upright 1007, when deployedin land use, extends externally of the hull 1002 across an outer face1002A and/or a side face 1002A of the planing surface.

FIGS. 39 and 40 show a sixth embodiment of amphibian according to thepresent invention. Like reference numerals have been used to identifycommon features with the fifth embodiment, which features will not bediscussed further here in detail. In particular, the differences betweenthese two embodiments will be described.

The amphibian 1001 includes a hull 1002, a vehicle body 1003, asuspension apparatus 1004 and a wheel 1005. Also provided are asuspension support structure 1011—which is connected directly with thevehicle body 1003—and a steering apparatus 1012.

The suspension apparatus 1004 comprises a suspension upright 1020, alsoknown as a king pin, an upper lateral suspension arm 1021 and a lowerlateral suspension arm 1022. In particular, the upper and lower lateralsuspension arms 1021, 1022 are wishbone-type suspension arms. The uppersuspension arm 1021 is operably-connected to the suspension upright 1020at a relative upper region of the suspension upright, when compared tothe relative lower connection of the lateral suspension arm 1022 and thesuspension upright 1020. Accordingly, an upper pivotal connection 1023is provided between the upper suspension arm 1021 and the suspensionupright 1020. Further, a lower pivotal connection 1024 is providedbetween the lower suspension arm 1022 and the suspension upright 1020.At opposed ends of the suspension arms 1021, 1022, one or more pivotalconnections 1025 is/are provided between the upper suspension arm 1021and an upper part of the support structure 1011 and one or more pivotalconnections 1026 (and/or 1033) is/are provided between the lowersuspension arm 1022 and a lower part of the support structure 1011. Ananti-roll bar 1027 is also provided to link the suspension apparatus1004 to a second suspension apparatus (not shown) which would be locatedopposite the first apparatus 1004.

As shown in FIG. 40, in particular, the suspension apparatus 1004includes a retraction ram 1028, for moving the suspension apparatus1004—and wheel 1005—from the vehicle-supporting position to theretracted position. By way of example, FIG. 39 shows the suspensionapparatus 1004 and wheel 1005 in a vehicle-supporting position. Further,FIG. 40 shows the suspension apparatus 1004 and wheel 1005 in aretracted position. A first, upper end of the retraction ram 1028 isconnected to an arm 1030, which forms part of the support structure1011. The second, lower end is connected to the vehicle body 1003.

Also, as shown in FIG. 40 in particular, a damper and spring assembly1029 is provided to allow the upper and lower suspension arms 1021, 1022and suspension upright 1020 to operate as a conventional suspension. Afirst end of the damper and spring assembly 1029 is connected to the arm1030 and the second end of the damper and spring assembly 1029 isconnected to the lower suspension arm 1022. The arm 1030 is pivoted atan opposite end to the connections with the retraction ram 1028 and thedamper and spring assembly 1029, and provides a pivot point 1033, whichis common with at least one of the pivotal connections 1026, aroundwhich the wheel 1005 and parts of the suspension apparatus 1004 canrotate between vehicle supporting and retracted positions.

In order to allow the suspension apparatus 1004 to move from avehicle-supporting position to a retracted position, both the upper andlower suspension arms 1021, 1022 are provided with a pivot point alongtheir length, to allow the suspension arms 1021, 1022 to be movedbetween retracted and protracted positions. The upper suspension arm ispivotal around the pivot point(s) 1025, provided at the junction of thesuspension arm 1021 and the support structure 1011. The lower suspensionarm 1022 is pivotal around pivot point(s) 1026, 1033, provided at thejunction of the lower suspension arm 1022 and the support structure1011. In particular, a part of the lower suspension arm 1022 is rigidlyconnected with the arm 1030 so that they are movable together. Further,a drop link 1031 is provided between the anti-roll bar 1027 and thelower suspension arm 1022, to provide increased rigidity and strength.

FIG. 40 shows, in particular, outer faces 1002A and/or side faces 1002Aof the planing surface across which the suspension upright 1020 extends,when deployed for land use. The suspension apparatus of FIGS. 39 and 40show a front-wheel only of an amphibian 1001. However, the suspensionapparatus 1004 may be used on any of the wheels of an amphibian 1001. Inparticular, although the amphibian 1001 shown in FIGS. 39 and 40 has nodrive going to the wheel 1005, the wheel 1005 may be a driven wheel.Further, in order to drive that wheel 1005, a step-down drive (notshown) may be provided as an integral structure with the suspensionupright or in addition to the suspension upright. As known by thoseskilled in the art, a step-down drive is capable of receiving an inputdrive from a relative higher location and producing an output drive to arelative lower location. Alternatively, the wheel hub 1010 may includeone or more hydraulic motors (not shown), or one or more electric motorsor electric hubs (not shown).

By way of an alternative, the retraction ram 1028 or the damper andspring assembly 1029 may be manually adjusted for varying the groundclearance of the amphibian 1001.

Although the suspension apparatus 1004 shown in FIGS. 39 and 40 isdrive-less, that suspension apparatus 1004 includes apparatus 1012 usedfor steering the amphibian 1001. The steering apparatus 1012 includes anarm 1036 which is operably connected, at connection 1032, to thesuspension upright 1020 in a mid-region of the suspension upright 1020,preferably between the connections 1023 and 1024. The other end of thearm 1031 is connected to input steering means, for example, handle barsor a steering wheel (not shown).

FIGS. 38, 39 and 40 show only one suspension apparatus 1004 and wheel1005 attached to the vehicle body 1003. However, it will be understoodthat any number of wheels could be used, in particular 3 wheels, and anappropriate number of suspension apparatuses 1004. Further, the wheels1005 may be driven or drive-less.

FIG. 41A shows an embodiment of the present invention which is similarto that shown in FIG. 38. Accordingly, like references have beenutilised for common features and only the differences will be discussed.In particular, the suspension upright 1007 and extended suspensionupright 1007A include a step-down drive 1060. As shown in FIG. 41B inparticular, the step-down drive includes an upper input end 1061 and alower output end 1062, when the suspension apparatus 1004 is in itsvehicle-supporting position. A cog 1063 is provided at each end 1061,1062 and is linked by a chain 1064, so that when either cog 1064 ismoved, corresponding rotation of the other cog 1063 is provided. The cog1063 at the input end 1061 is driven by a shaft 1065, itself drivendirectly or indirectly by a prime mover, as exemplified by an engine1066. One or more universal joints 1067 or equivalents are used toconnect the engine 1066, shaft 1065 and cog 1063. The cog 1063 at theoutput end 1062 drives the wheel hub 1010 and the wheel 1005.Accordingly, an input drive from a prime mover is stepped-down to alower height with respect to the ground the amphibian is standing on todrive one or more wheels.

FIG. 42A shows a hull of an amphibian according to the presentinvention. The hull is shaped to provide good hydro-dynamics. Further,no cut-out or other abnormalities, and/or parts of the suspensionapparatus, drive shaft or wheel would be submerged and/or contactable bywater, when the amphibian has the suspension apparatus 1004 retracted,for use on water. By contrast, FIG. 42B shows a hull of an amphibian inwhich cut-outs 1050 are provided to locate the suspension apparatusesand/or wheels in a retracted position thereof. Accordingly, a hull shownin FIG. 42A has better hydro-dynamics than a hull shown in FIG. 42B.

Referring next to FIG. 43, there is shown an amphibian 1110 according toa seventh embodiment of the present invention. The amphibian 1110 mayinclude any or all of the features described above, in any combination,with the following particular features.

A number of suspension layouts for amphibians have been proposed. Suchsuspension layouts allow sprung and damped movement of the wheels whenthe amphibian is on land, and retraction of the wheels for use of thevehicle on water. The suspension is generally inboard of the wheel, forexample as known from US 2005/0034646 to Royle. This has thedisadvantage that the width of the hull between the wheels is restrictedfor a given width of the amphibian, as at least a lower suspension armmust project through the plane of the hull to support the wheel inprotracted land mode. Space must also be allowed for suspension reboundtravel. An example of this restriction may be seen from the applicant'sco-pending application published as US 2007/0,006,788 A1.

The present invention provides an amphibian according to claim 149.Thus, the width of the hull is not restricted by the suspension.

FIG. 43 shows an amphibian 1110 according to the present invention. Theamphibian 1110 comprises a hull 1112 being a buoyant vessel, and havinga pair of rear wheels 1120 in close proximity (i.e. adjacent to eachother) arranged as effectively one wheel. The closely spaced pair ofwheels are located on the central longitudinal axis of the amphibian.

The hull 1112 is V-shaped in vertical cross-section. The amphibian 1110also has two or more front wheels (not shown).

The amphibian 1110 includes a motor (not shown) or a similar powersource to provide power through a transmission to the rear wheels 1120.Alternatively, the motor may power the front wheels only, or may powerthe front wheels and rear wheels.

The rear wheels 1120 are connected to the hull 1112 by a suspensionassembly 1122. The suspension assembly 1122 comprises a pair of trailingarms 1124, extending rearwardly from the hull 1112. The trailing armsare rotatably connected to a chassis of the vehicle (within andsupporting the hull 1112) at pivots (not shown).

The rear wheels 1120 are rotatably mounted to inboard sides of thetrailing arms 1124, each wheel rotating about its own axis. The wheels1120 are rotatably mounted to distal ends of the arms 1124, distal tothe pivots, by mounts 1126. The mounts 1126 allow rotation of the wheels1122 about their common rotational axis X-X. The mounts 1126 arecompliantly secured on trailing arms 1124 and allow relative movementbetween the wheels 1120 and arms 1124 about a substantially horizontalaxis, parallel to a longitudinal axis of the hull, in order to allow thehull 1112 to roll in use on land, but to maintain good tyre contact withthe ground. Although tyres of a substantially square tread cross-sectionare shown in the figures, tyres of a more rounded cross-section as usedon motorcycles, may be used instead. The mounts 1126 may each comprise aball joint.

The two rear wheels 1120 are preferably connected by an axle (notshown). The axle assists in keeping the wheels 1120 parallel.Alternatively, the pair of wheels may not be connected by an axle.

Each trailing arm 1124 is spring-mounted to the vehicle, preferably bytorsion bars (not shown) provided at or adjacent to the pivots. Aseparate torsion bar is preferably provided for each arm 1124. Thetorsion bars extend laterally towards the centre of the hull 1112.

The wheels 1120 may be driven via a shaft acting through a differential(not shown) in the axle. The differential may be in the centre of theaxle, or may be offset to one side.

Alternatively, the wheels 1122 may each be driven by a belt or a chain.The belt or chain may be located partially or wholly inside one or eacharm 1124. Alternatively, a driven toothed wheel or sprocket may beprovided at the centre of axle.

The amphibian 1110 may be powered on water by one or more jet drives1140. The or each jet drive has one or more jet nozzles through whichwater is expelled to provide propulsion. The jet nozzles may be locatedbetween the wheels 1120.

The suspension 1122 is provided with a retraction mechanism, in order toretract the wheels 1120 for use of the amphibian 1110 on water. Theretraction mechanism may comprise cranked torsion bars (not shown). Eachtorsion bar comprises an aligned portion substantially aligned with thepivots, and defining a rotational axis of the torsion bar. Each torsionbar further comprises a cranked portion perpendicular to the axis of thetorsion bar. The cranked portion is at or near an inboard end of eachtorsion bar.

An actuator may be attached to each cranked portion. Contraction orextension of the actuators can be used to control retraction ordeployment of the wheels 1120. Alternatively, a single actuator may beconnected to a cranked portion of the torsion bars of both of the pairof wheels 1120 (the single actuator could act on a bar connecting thecranked portions).

Preferably, each arm is connected to its own laterally outwardlyextending bar, each outwardly extending bar having a cranked portion,the two cranked portions connected by a connecting strut extendinglaterally.

Alternatively, the retraction mechanism may be in the form of one ormore hydraulic struts (not shown). The hydraulic struts may be connectedbetween the arms 1124 or axle and the hull 1112. The hydraulic strutsmay act both as dampers and also as hydraulic actuators to retract anddeploy the wheels. Suitable hydraulic struts are known from publicationUS 2003/0047899.

The hull 1112 has recesses 1136, for receiving the arms 1124. Therecesses 1136 are shaped to allow retraction of the wheels.

In a retracted position, the wheels 1120 may be within the length of thehull 1112. The hull 1112 extends over and beyond the wheels 1120 intheir retracted position. This location of the wheels improves spraycontrol when the amphibian is planing on water, and the wheels are inthe retracted position.

The above description relates to the use of the suspension assembly 1122on rear wheels of an amphibian. Alternatively, the same or similarsuspension assembly 1122 may be used for the front wheels of anamphibian. The arms 1124 may extend rearwardly and support front wheelsas described above. Alternatively, the arms 1124 may extend forwardly,such that the supported front wheels are forward of the pivots. The rearwheels 1120 may be supported on forwardly extending arms. The featuresdescribed above would be the same or reversed as would be clear to aperson skilled in the art.

The amphibian may have a total of three wheels, in the form of a pair offront wheels and a single rear wheel. The amphibian may have fourwheels, being a front pair of wheels and a rear pair of wheels providedadjacent one another in close proximity. One or both of the front andrear pair of wheels may have a suspension assembly as described. Theamphibian may have more than four wheels, for example, the amphibian mayhave six wheels (e.g. three pairs of two wheels).

Referring next to FIGS. 44 and 45, there is shown an amphibian 1210according to an eighth embodiment of the present invention. Theamphibian 1210 may include any or all of the features described above,in any combination, with the following particular features.

Amphibians have been proposed and produced in various formats. Althoughamphibian bicycles have been proposed, the smallest engine drivenamphibians have been motorcycles. Lehrberger (DE 19831324C2), Gong (U.S.Pat. No. 6,540,569), and Buchanan (GB 2,254,831) all disclose designsfor amphibian motorcycles. But none of these designs have beenmanufactured or sold. There is clearly room for improvement over thisprior art.

Amphibians are dual purpose vehicles, and must therefore be equallyusable on land as they are on water. Different classes of vehiclegenerate different expectations in the potential buyer's mind.Motorcycles are generally sold on a sleek image, with an implicitpromise of fast acceleration and fast, steeply leaning cornering. Thethree machines described above, however, are heavy, wide, and bulbous inshape.

The addition to a motorcycle of equipment needed for travel on waterleads to a large increase in weight; particularly where twin marine jetdrives are used. The casings of these jets are usually castings; whichmakes them very heavy. This weight will blunt performance on road, andreduce roadholding capability on corners. The width of the motorcyclemust also be increased compared to the convention for a purely roadmachine, to provide both buoyancy and stability on water. But thisincreased width limits the angle through which the machine can be leanedon corners on road. The additional weight and width will make themotorcycle feel cumbersome on road. If the machine falls over, eitherdue to a skid or through impact when parked, it will be very difficultto return it to the upright riding position. It is clearly preferablefor a vehicle which is too heavy to be lifted by the rider to beself-stable. Finally, the bloated appearance of an amphibiousmotorcycle's bulbous bodywork will limit its market appeal.

It is necessary, therefore, is to address these problems with anamphibian which will provide adequate performance on water withoutunacceptable compromises in use on land. Implicit in this equation isthe avoidance of a mismatch between expectation and delivery. If at thesame time, the utility of the amphibian is increased, a still moreattractive package may be developed.

The use of twin jet drives in amphibians is known, not least from theprior art cited above. The advantage of twin jets is that the amphibiancan rise rapidly onto the plane on water—perhaps one or two secondsfaster than an equivalent machine with a single jet drive. The drawbacksof twin jets are in the weight of the driveline, cost, and packaging;and a reduction in top speed on water due to the increased pumpinglosses through the additional jet drive. The top speed might, forexample, be reduced by four knots for a compact amphibian.

So the choice of single or twin jets is not a matter of either doing thesame job as well as the other; but a more conscious decision based onthe market sector at which the amphibian is aimed. The ultimate highperformance amphibian will use a single jet drive, but may be regardedas more difficult to ride; but a twin jet machine will be easier toride, less ultimately fast but more relaxing. Although twin jets may beassumed to be heavier than a single jet drive, the applicant hasestablished a surprising result occurs when comparing the two layouts.To provide equivalent performance from twin jets as from one jet, thetwin jets will be specified as being of smaller diameter than theequivalent single jet. This reduces the tip speed of the jet bladescompared to the single jet drive; which makes the twin jets less liableto cavitation at speed. It is also found that as forces at the tips ofthe blades go up as the square of the rotational speed, a smaller jetcan be built more lightly than a single jet, because it is of smallerdiameter. Hence, twin jets may in themselves be lighter than a singlejet drive; and may still be lighter overall, even when a more complextransmission is necessarily specified than for a single jet drive.

Other options to consider in managing the customer's expectations wouldinclude performance available on land. One option here is to offer lesspower on land than on water, as described in the applicant's U.S. Pat.No. 7,207,851B1. Another option in managing expectations is to amend thelayout of the vehicle; particularly in making it more stable than amotorcycle by providing more wheels. This in turn would also increasethe carrying capacity of the vehicle, both in volume and in weight. Sothe overall package would move away from ultimate performance towardsutility. It is considered that the market for ultimate performanceamphibians is small—as for “supercars” on road; but greater marketsuccess can be obtained with a slightly slower, but much more usable,amphibian.

It is considered that a combination of three wheel stations 1220, 1222,1224 with twin jet marine drives 1230, 1232 (each having an intake 1234and outlet 1236) provides an ideal combination of accessible marineperformance, failsafe road stability, and carrying capacity. Front andrear retractable wheel suspension assemblies 1260, 1280 are provided.These characteristics may be combined with ride on seating 1240, whichprovides best visibility in all directions; and being aligned with thelongitudinal centre line X-X of the amphibian 1210, gives good lateralweight distribution, even when there is only the rider on the amphibian.

The increase in load carrying area brought about by the increase in thenumber of wheels is considered to be more than adequate compensation forthe concomitant increase in amphibian weight. Where three wheels areused, the use of two front wheels offers good stability on road, whiletwin jet drives 1230, 1232 can be easily packaged either side of thesingle rear wheel. This is in contrast to U.S. Pat. No. 5,690,046 toGrzech, where the single front wheel requires complex retractionarrangements and the twin rear wheels only allow use of a single jetdrive.

Referring now to FIGS. 1 to 4 and FIG. 6, amphibian 10 can be seen tocomprise a longitudinal axis L-L running from a front bow end 12 to arear stern end 14 of the amphibian 10, which longitudinal axis can beany longitudinal axis spaced laterally or vertically, as indicated bythe arrows. Indeed the longitudinal axis may lie in or out of thehorizontal plane of the amphibian, i.e. may be inclined to thehorizontal. In addition, amphibian 10 can be seen to comprise atransverse axis T-T running from a left port side to a right starboardside of the amphibian 10, which transverse axis can be any transverseaxis spaced laterally or vertically, as indicated by the arrows. Indeedthe transverse axis may lie in or out of the horizontal plane of theamphibian, i.e. may be inclined to the horizontal.

The amphibian can be seen to comprise at least three retractable wheels51, 53, 55, at least two of the retractable wheels 51, 53 beingretractable about an axis substantially parallel to, or offset by anangle α of up to 40 degrees from, the longitudinal axis L-L of theamphibian 10. At least one of the retractable wheels, the thirdretractable wheel 55 is retractable about an axis substantially parallelto, or offset by an angle β of up to 40 degrees from, a transverse axisT-T of the amphibian.

Preferably the angle α is any angle in the range of from 0 degrees to 40degrees, more preferably from 0 degrees to 30 degrees, even morepreferably from 0 degrees to 20 degrees, and preferably from 0 degreesto 15 degrees. Preferably the angle β is any angle in the range of from0 degrees to 40 degrees, more preferably from 0 degrees to 30 degrees,even more preferably from 0 degrees to 20 degrees, and preferably from 0degrees to 15 degrees.

It will be appreciated that the axis of wheel retraction parallel to, oroffset from, the longitudinal axis L-L of the amphibian may spacedlaterally or vertically from the longitudinal axis L-L. Similarly, theaxis of retraction parallel to, or offset from, the transverse axis T-Tof the amphibian may be spaced laterally or vertically from thetransverse axis T-T.

Although several embodiments of amphibian have been described above, anyone or more or all of the features described (and/or claimed in theappended claims) may be provided in isolation or in various combinationsin any of the embodiments. As such, any one or more these features maybe removed, substituted and/or added to any of the feature combinationsdescribed and/or claimed. For the avoidance of doubt, any of thefeatures of any embodiment may be combined with any other feature fromany of the embodiments.

Whilst in certain of the above embodiments a single internal combustionengine is used to both drive a road wheel in land mode operation andalso to power the jet drive(s) in marine mode, separate engines could beprovided, one for the road wheel(s) and another for the jet drive(s).Indeed, the engines may not be internal combustion engines, but mayinstead take the form of any primer mover (electric, hydraulic,pneumatic, hybrid, or otherwise, as required). Also the jet drive(s)could be replaced by a propeller(s) or any other marine propulsionmeans.

It will be appreciated that the present invention is not limited tohandlebar steering; a steering wheel may be beneficially employed.Amphibians according to the present invention may be rear wheel drive,front wheel drive or all wheel drive. Indeed, the amphibians may be onewheel drive, two wheel drive or three wheel drive. To supplement thethree wheel configuration of the present invention, stabilising devicesmay be beneficially employed. One form of stabilising device may takethe form of two wheels or skids provided in the rear half of theamphibian, preferably spaced laterally from the longitudinal centre lineof the amphibian. These stabilising devices may be retractable anddeployed only in certain operating conditions (e.g. when learning tooperate the amphibian for the first time).

Whilst preferred embodiments of the present invention have beendescribed above and illustrated in the drawings, these are by way ofexample only and non-limiting. It will be appreciated by those skilledin the art that many alternatives are possible within the ambit of theinvention, as set out in the appended claims.

1-208. (canceled)
 209. An amphibian having two front wheels, a singlerear wheel, and a body; wherein seating is provided for at least onerider to sit astride the body, wherein a water jet unit is provided forpropulsion in water and wherein the water jet unit is positioned aheadof the rear wheel.
 210. An amphibian according to claim 209, wherein therear wheel is driven to power the vehicle on land.
 211. An amphibianaccording to claim 209, wherein the front wheels are driven to power thevehicle on land.
 212. An amphibian according to claim 209, wherein thewater jet unit is longitudinally aligned with at least part of the rearwheel.
 213. An amphibian according to claim 209, wherein at least onedeflector is provided in order to divert the output from the water jetaway from said rear wheel.
 214. An amphibian according to claim 213,wherein the deflector is formed as a chevron shape to deflect watereither side of the rear wheel.
 215. An amphibian having two frontwheels, a single rear wheel, and a body; wherein seating is provided fora rider to sit astride the body, wherein a suspension connects the frontwheels and the rear wheel to the body and the suspension is arrangedsuch that the body can lean about a longitudinal axis.
 216. An amphibianaccording to claim 215, wherein a water jet unit is provided forpropulsion in water and said water jet unit is offset from a centrallongitudinal axis of the body.
 217. An amphibian according to claim 215,wherein pontoons are provided either side of the rear wheel.
 218. Anamphibian according to claim 217 wherein an output nozzle of the waterjet unit is located in a pontoon.
 219. An amphibian comprising at leastthree retractable wheels, at least two of the retractable wheels beingretractable about a first axis of the amphibian, and at least one of theretractable wheels being retractable about a second axis wherein saidfirst and second axes are not parallel relative to one another.
 220. Theamphibian of claim 219, wherein said first axis is substantiallyparallel to, or offset by up to 40 degrees from, a longitudinal axis ofthe amphibian, and said second axis is substantially parallel to, oroffset by up to 40 degrees from, a transverse axis of the amphibian.221. The amphibian of claim 219, wherein said first axis issubstantially parallel to, or offset by up to 20 degrees from, alongitudinal axis of the amphibian, and at said second axis issubstantially parallel to, or offset by up to 20 degrees from, atransverse axis of the amphibian.
 222. The amphibian of claim 219,wherein said first and second axes are perpendicular to one another.